Can't use sculpt brushes unless I press control
It sounds like your normals have been inverted on your model, since CTRL is usually used to invert a brush. This is a pretty easy fix, if it's the case, but you do have to go into edit mode. I hope you don't have too many faces! 

Go into edit mode, select everything, then on your toolshelf (on the left of your screen by default) go to your Shading/UV tab and click on 'recalculate' (you should find it under 'normals'). This should fix your problem, if it's normals-related.